Data writer with flux density insert

ABSTRACT

A data writer may be generally configured at least with a write pole adjacent to and separated from a side shield and a trailing shield. The side shield may be formed of a first material and configured with a trailing box region that is at least partially filled with a flux density insert formed of a second material that is different than the first material.

RELATED APPLICATION

The present application is a continuation of copending U.S. patentapplication Ser. No. 13/931,340 filed Jun. 28, 2013 which will issue asU.S. Pat. No. 9,196,267 on Nov. 24, 2015.

SUMMARY

Some embodiments are generally directed to a magnetic element capable ofbeing used to program data bits in various data storage environments.

In accordance with an example embodiment, a write pole may be positionedadjacent to and separated from side and trailing shields. The sideshield may be formed of a first material and configured with a trailingbox region that is at least partially filled with a flux density insertformed of a second material that is different than the first material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block representation of an example data storage deviceconstructed and operated in accordance with various embodiments.

FIG. 2 illustrates an air bearing view block representation of anexample magnetic element capable of being used in the data storagedevice of FIG. 1.

FIG. 3 shows an air bearing view block representation of a portion of anexample magnetic element configured in accordance with some embodiments.

FIG. 4 displays an air bearing view block representation of a portion ofan example data writer constructed in accordance with variousembodiments.

FIG. 5 illustrates an air bearing view block representation of a portionof an example data writer configured in accordance with variousembodiments.

FIG. 6 is an air bearing view block representation of a portion of anexample data writer constructed in accordance with some embodiments.

FIG. 7 provides an air bearing view block representation of a portion ofan example data writer configured in accordance with variousembodiments.

FIG. 8 is an air bearing view block representation of a portion of anexample data writer constructed in accordance with some embodiments.

FIG. 9 is a flowchart and associated illustrations for an example datawriter fabrication routine in accordance with various embodiments.

DETAILED DESCRIPTION

Demand for high data capacity and fast data access speeds in reducedform factor data storage devices has emphasized the physical size oftransducing components like data readers, data writers, and magneticshields. Such reduction in physical size may correspond with diminishedperformance as inadvertent magnetic conditions like shunting and domainwall movement degrade operating capabilities of the transducingcomponents. While diverse shielding configurations have been proposed tomitigate inadvertent magnetic conditions, issues like data erasurecontinue to inhibit optimization of transducing components. Hence, thereis a continued industry demand for magnetic shielding with optimizedmagnetic performance in reduced form factor data storage devices.

With magnetic shielding issues in mind, a data writer can be configuredwith a write pole positioned adjacent to and separated from side andtrailing shields with the side shield formed of a first material andconfigured with a trailing box region that is at least partially filledwith a flux density insert formed of a second material that is differentthan the first material. The positioning of the flux density insertdowntrack and along the trailing edge of the write pole can optimizewrite field and write field gradient while enhancing shielding of thewrite pole. The flux density insert and trailing box region may be tunedto define diverse write pole magnetic extents and contain magnetic fluxwithin the predetermined magnetic extent, which corresponds with reducederasure conditions and maintaining high magnetic fields from the writepole.

A magnetic element that utilizes tuned trailing box and flux densityinsert may be implemented into an unlimited variety of data storageenvironments. FIG. 1 provides a block representation of a portion of anexample data storage device 100 operated in a data storage environmentin accordance with various embodiments. The data storage device 100 isshown in a non-limiting configuration where a transducing head 102 canbe positioned over a variety of locations on a magnetic storage media104 where stored data bits 106 are located on predetermined data tracks108. The storage media 104 can be attached to one or more spindle motors110 that rotate during use to produce an air bearing 112 on which atleast a write pole 114, return pole 116, and magnetic shield 118 of thetransducing head 102 reside and interact through to program the databits 106 to predetermined magnetic orientations.

While the transducing head 102 is displayed exclusively as a magneticwriter, one or more transducing elements, such as a magneticallyresponsive reader can concurrently be present in the transducing head102 and communicating with the data storage media 104. Continuedemphasis on minimizing the physical and magnetic size of the transducinghead 102 is compounded by the increased data bit density and reduceddata track 108 width of the data storage media 104 to stress the formand function of magnetic shields to define and maintain a predeterminedmagnetic extent for the write pole 114 that allows access to individualdata bits 106 without inadvertently imposing magnetic flux onto adjacentdata tracks 108 in an erasure condition.

FIG. 2 displays an air bearing view block representation of a portion ofan example transducing element 120 capable of being implemented into thedata storage device 100 of FIG. 1. As shown, a trapezoid shaped writepole 122 is positioned between lateral side shields 124 along the X axisand uptrack from a trailing shield 126. The shields 124 and 126 may beformed of common or dissimilar magnetically soft materials like NiFe andCoFe that maintain magnetic fields proximal the write pole 122 whilekeeping errant external magnetic fields from entering a predeterminedmagnetic extent and interfering with the operation of the write pole122.

The write pole 122 can be tuned by adjusting the shape of the write pole122, the non-magnetic gap distance between the write pole 122 and sideshields 124, and the side shield sidewall angles θ₁ and θ₂ to define thescope of magnetic flux transmission from the write pole 122. That is,the side shields 124 can be individually or collectively shaped to havesidewalls 128 and 130 angled to be similar or dissimilar compared to theangle θ₃ of the write pole sidewalls 132 from the write pole tip 134 toa trailing box region 136 proximal the trailing edge 138 of the writepole 122. As shown, the side shields sidewalls 130 are shaped to providea throat region 140 that is proximal the write pole tip 134 and filledwith non-magnetic insulating material, such as alumina, to reduceshunting of magnetic flux from the write pole 122 to the side shields124.

Similarly, the trailing box region 136 is defined by the side shields124 and filled with non-magnetic insulating material to reduce oreliminate shunting between the write pole 122 and downtrack portions ofthe side shields 124 as well as the trailing shield 126. The removal ofsoft magnetic shielding material to define the trailing box regions 136can be tuned to have a width 142, thickness 144 along the Y axis, anddistance 146 from the trailing edge 138 of the write pole 122 to providea balance of shielding capability and magnetic shunting. The size andfunction of the trailing box region 136 may be influenced by thematerial and thickness of the shield seed 148, trailing shield layer150, and side shield 124, which can provide a predetermined downtrackand cross-track shielding capability that allows the trailing box region136 to be larger to mitigate shunting risk without degrading shieldingcapability of the trailing 126 and side 124 shields.

By positioning the side shields 124 proximal the write pole 122 near thewrite pole tip 134, more magnetic flux is maintained in the write pole122 to increase write field amplitude and gradient. However, the lack ofany magnetic material along the trailing edge distance 146 can allowmagnetic flux to be present distal the write pole 122, which can lead tounwanted erasure of data bits positioned on data tracks adjacent to thepredetermined magnetic extent of the write pole 122. Accordingly, thetrailing box region 136 can be partially or completely filled with amagnetic flux density insert that reduces shunting between the shields124 and 126 and write pole 122 while preserving increased magnetic fieldamplitude and gradient provided by the lack of soft magnetic shieldingmaterial proximal the trailing edge 138 of the write pole 122.

FIG. 3 displays an air bearing view block representation of a portion ofan example magnetic element configured in accordance with someembodiments to have magnetic flux density inserts 162 that fill thetrailing box region 164 proximal the trailing edge 166 of the write pole168. The magnetic flux density inserts 162 can have similar ordissimilar configurations to provide a predetermined saturation fluxdensity (B_(s)) that is lower than the side 170 and trailing 172shields, but higher than the non-magnetic insulating material 171 thatseparates the write pole 168 from the shields 170 and 172.

Such difference in saturation flux density between the flux densityinserts 162 and the shields 170 and 172 can be achieved, in someembodiments, by configuring at least one flux density insert 162 as asolid layer of material with a continuous saturation flux density. Inthe non-limiting embodiment shown in FIG. 3, each flux density insert162 is configured as a vertical lamination of multiple differentmaterials that each have different saturation flux densities that beginfrom a horizontal plane, along the X axis, a predetermined distance 174from the write pole tip 176 of the write pole 168 or from the trailingshield 172. The respective flux density inserts 162 may further be tunedby maintaining the side shield sidewall 178 angle, which may match or bedifferent from the pole sidewall 180 angle, from the write pole tip 176to the trailing shield 172.

While the number of constituent layers, thickness of those layers, andsize of the trailing box region 162 can be tuned to be different fromthe example embodiment shown in FIG. 3, the trailing box may have alateral depth of 50-500 nm along the X axis and more than, less than, orequal to half of the write pole longitudinal length along the Y axisfrom tip 176 to the trailing edge 166. The vertical laminationconfiguration of the flux density inserts 162 can allow a gradualreduction or increase in saturation flux density along the downtrackdirection. In other words, the first 182, second 184, third 186, andfourth 188 flux density insert layers can have increasing or decreasingsaturation flux densities in accordance with various embodiments toprovide a predetermined saturation flux density profile along the Y anddowntrack axis to reduce the risk of erasure while optimizing writefield amplitude and field-gradient for the write pole 168.

The continuous lateral extension of each flux density insert layer alongthe X axis can provide increased shielding capabilities over filling thetrailing box region 164 with non-magnetic material that allows errantmagnetic flux to uniformly saturate in the cross-track direction,perpendicular to the downtrack direction. Although, the lateralorientation of the flux density insert layers may also migrate fluxtowards the write pole 168 and increase the risk of shunting. FIG. 4 isan air bearing view block representation of a portion of an examplemagnetic element 190 employing flux density inserts 192 each tuned inaccordance with various embodiments to be horizontal laminations, asopposed to the vertical lamination displayed in FIG. 3.

As shown in FIG. 4, each flux density insert 192 fills the trailing boxregion 194 on either side of the write pole 196 and each constituentflux density insert layer continuously extends with a vertical sidewall198 to contact both the side shield 200 and trailing shield 202. Thevertically aligned insert layer sidewalls 198 that match thelongitudinal axis 204 of the write pole 196 can reduce the distancebetween the flux density insert 192 and the trailing edge of the writepole 196 by having different angular orientations than the side shieldsidewalls 206 and pole sidewalls 208. The amount of non-magneticinsulating material between the trailing edge of the write pole 196 andflux density inserts 192 can be tuned, along with the material selectionof the flux density insert layers, to provide increasing saturation fluxdensity as measured from the longitudinal axis 204 of the write pole196.

For example, the first flux density insert layer 210 that is positionedclosest to the write pole 196 can have a lower saturation flux densitythan the second 212, third 214, and fourth 216 layers that arerespectively configured with increasing saturation flux densities. Suchincreasing saturation flux density laterally from the write pole 196 canprovide reduced migration of magnetic fields from and towards the writepole 196 while providing a continuous magnetic flux pathway from theside shields 200 to the trailing shield 202 throughout the trailing boxregions 194. Various embodiments tune the at least two of theconstituent flux density insert layers to have a common saturation fluxdensity while other embodiments configure the flux density inserts 192to have a single saturation flux density, such as 0.3 Tesla,corresponding to different materials having differing thicknesses asmeasured along the X axis.

The diverse varieties of flux density insert configurations illustratedin FIGS. 3 and 4 show how write pole and shield performance can be tunedto provide a predetermined write field amplitude and field-gradient withminimal risk of inadvertent erasure conditions. The direct contact ofthe side 200 and trailing 202 shields can operate in concert with theflux density inserts 192 to direct errant magnetic fields around andaway from the write pole 196. However, the contact of the side 200 andtrailing 202 shields can increase shield saturation and risk of writepole 196 shunting. While the side 200 and trailing 202 shields can bedisconnected by extending the trailing box region 194 laterally toenhance write pole performance, the increased trailing box region 194can correspond with higher erasure condition risk as magnetic fieldsmigrate farther from the write pole 196 than if the trailing box region194 had a closed lateral end.

Accordingly, the example data writer 220 of FIG. 5 displays how side 222and/or trailing 224 shields can be connected via flux density inserts226 and 228 in accordance with some embodiments. Connecting the side 222and trailing 224 shields via the flux density inserts 226 and/or 228 canreduce shield saturation strength while maintaining shieldingperformance. The position of the flux density inserts 226 and 228 innotches of a trailing box region 230 allows the trailing box length 232from the trailing edge of the write pole 234 to be filled withnon-magnetic insulating material, which may correspond with increasedwrite field amplitude and field-gradient. It should be noted that whilethe dissimilar insert 226 and 228 configurations shown in FIG. 5 ispossible, such is not limiting as various embodiments use commonlyconfigured inserts on opposite sides of the write pole 234 to providesymmetric shielding on either side of the longitudinal axis of the writepole 234 along the Y axis.

As shown in FIG. 5, each trailing box region 230 has a first thickness236, as measured along the Y axis, proximal the write pole 234 and areduced second thickness 238 defined by a notch sidewall 240 that can beangled to gradually or abruptly transition between the thicknesses 236and 238. The ability to magnetically connect the side 222 and trailing224 shields via the flux density inserts 226 and 228 allows throttledmagnetic field migration between shields 222 and 224 that providesreliable magnetic shielding without increased erasure condition risk.Such magnetic connection between the side 222 and trailing 224 shieldscan be tuned through flux density insert 226 and 228 material selectionand configuration, as illustrated by the single continuous flux densityinsert 228 compared to the horizontal lamination flux density insert 226that comprises first 240 and second 242 flux layers having differentsaturation flux densities, which may be a non-magnetic saturation fluxdensity. Through the tuned configuration of one, or both, flux densityinserts 226 and 228 to continuously extend along the notch length 244and physically separate the shields 222 and 224, magnetic flux can beisolated to the respective shields 222 and 224 while errant magneticflux is allowed to be shunted by the flux density inserts 226 and 228 tomitigate flux concentration distal the write pole 234. The combinationof a notched trailing box region 230 and tuned flux density insert 226and 228 that fills the notch while separating the side 222 and trailing224 shields allows a balance between risk of shunting due to the removalof shielding material proximal the trailing edge of the write pole 234and risk of erasure due to the lower saturation flux densities of theflux density inserts compared to non-magnetic insulating material andmagnetic shields 222 and 224.

The tuned data writer 220 can provide optimized magnetic shielding andwrite pole 234 performance, but may induce increased complexity andmanufacturing processing, especially in reduced form factor data storagedevices. FIG. 6 is an air bearing view block representation of anexample data writer 250 constructed in accordance with variousembodiments to separate side 252 and trailing 254 shields with fluxdensity inserts 256 and 258 that respectively occupy trailing boxregions 260 that have a uniform thickness 262 that extends along the Xaxis. The use of uniform thickness 262 trailing box regions 260 canreduce complexity and processing time versus varying thickness trailingbox configurations, like trailing box region 230 of FIG. 5.

The lack of a trailing box notch can further allow for flux densityinsert sidewall and length tuning. In the non-limiting example shown inFIG. 6, flux density insert 256 has a continuous material that extends alength 264 that is less than the trailing box region length 266 and isconfigured with a sidewall 268 angled to match the angle of the sideshield 252 sidewall 270 proximal the write pole tip 272 of the writepole 274. The reduced length 264 and angled sidewall 268 of the fluxdensity insert 256 can provide a non-magnetic insulating material toreduce risk of magnetic shunting while the tuned saturation flux densitymaterial of the flux inert 256 optimizes shielding and magnetic fieldmigration between the side 252 and trailing 254 shields.

Various embodiments tune a flux density insert like flux density insert258 with a length that matches the underlying side shield 252 along ahorizontal plane positioned a predetermined vertical distance from thewrite pole tip 272. The flux density insert 258 can have a sidewall 276angled to match the side shield sidewall 270 and be dissimilar from thewrite pole sidewall 278 angle O₂ so that the side gap between the writepole 274 and side shield 252 increases along the downtrack direction andY axis so that more non-magnetic insulating material lies between theflux density insert 258 and the write pole 274 than the write pole tip272 and the side shield 252. Such varying side gap can allow the fluxdensity insert 258 to be farther from the trailing edge of the writepole 274 and reap a reduced shunting risk with increased shieldingperformance supplied by the larger flux density insert 258 compared tothe reduced length flux density insert 256.

It should be noted that while the example data writers 220 and 250respectively employ differing flux density inserts on opposite lateralsides of a write pole, such configuration is not required or limiting asthe flux density inserts can be configured with identical sizes, shapes,and materials in various embodiments. With the proliferation of highdata bit density data storage devices that reduce data track widths andhave large quantities of stray magnetic fields, the lack of a magneticshield proximal the write pole tip can correspond with degraded magneticfield amplitude and data writing accuracy. With those challenges inmind, a box shield can be employed to surround the write poles 234 and274 of FIGS. 5 and 6, respectively, with soft magnetic shield materialinstead of having side shields 222 and 252 separated by non-magneticinsulating material, as displayed in FIGS. 5 and 6.

FIG. 7 provides an air bearing view block representation of an exampledata writer 280 constructed with a box shield 282 that continuouslyextends around the write pole tip 284 in accordance with someembodiments. The box shield 282 may be a single continuous layer of softmagnetic material or a plurality of shield portions, such as a leadingand side shields, contacting at one or more seams. The box shield's 282position uptrack of the write pole tip 284 can reduce the accumulationof magnetic flux in the throat region 286 between side shield portions288 and the consequential inadvertent erasure condition.

Conversely, the increased amount of magnetic material in the box shield282 can increase the chance of magnetic saturation and unwanted shuntingwith the write pole 290. Such risk may be mitigated by configuringtrailing box regions 292 to extend uptrack from the trailing edge 294 toeven beyond the median transverse plane 296 of the write pole 290. Theincreased size of the trailing box regions 292 allows for larger fluxdensity inserts 298 with greater shield flux influence via the tunedsaturation flux density of the constituent layers 300, 302, and 304.That is, the material and shape of the flux density inserts 298 canimpart a greater influence on the magnetic saturation of the box shield282 due to the larger physical size of the constituent insert layers300, 302, and 304.

The flux density insert layers 300, 302, and 304 along with the trailingbox sidewall 306 can be shaped, as shown, at a predetermined uniformangle that maintains or increases a side gap distance between the fluxdensity inserts 292 and the write pole 290. Such angled sidewalls cancomplement the tuned construction of constituent insert layers thatpositions increasing saturation flux densities according to distancefrom the write pole 290. As an example, layers 300, 302, and 304 can beconstructed with different materials that have progressive saturationflux densities that increase from layer 300 to layer 302 to layer 304.In some embodiments, one or more of the insert layers 300, 302, and 304can extend to contact the trailing shield 308 while other embodimentsmagnetically connect the trailing 308 and box 282 shields exclusively bythe flux density inserts 298.

The tuned shape and saturation flux densities of the flux densityinserts 298 may mitigate inadvertent shunting while optimizing writepole 290 operation. Various embodiments further adjust the amount ofmagnetic material positioned in the trailing box regions 292 to reducethe amount of saturated magnetic material proximal the write pole 290.FIG. 8 generally displays an air bearing view block representation ofsuch a configuration in an example data writer 320. As shown, the writer320 has first 322 and second 324 flux density inserts occupying lessthan all of the respective trailing box regions 326 positioned onopposite lateral sides of the write pole 328. The trailing box regions326 each extend beyond a median transverse plane of the write pole 328and are filled with a combination of flux density insert layers andnon-magnetic insulating material that continuously extends to separatethe write pole 328 from the box 330 and trailing 332 shields.

With the combination of the flux density inserts 322 and 324 along withthe non-magnetic insulating material occupying the trailing box regions326 in predetermined ratios, less magnetic material is proximal thewrite pole 328 to reduce the chance of shunting and the flux densityinserts 322 and 324 that are present proximal the write pole 328 havetuned magnetic saturation flux densities that minimize the chances ofshunting while providing accurate magnetic shielding. While notrequired, the first flux density insert 322 is disconnected from thetrailing shield 332 and positioned uptrack of the non-magnetic materialfilling the trailing box region 326 while the second flux density insert324 contacts the trailing shield 332 and is downtrack of thenon-magnetic material in the trailing box region 326.

In some embodiments, the differently configured flux density inserts 322and 324 are used concurrently to provide varying magnetic shielding andflux profiles for the lateral side shield portions of the data writer320. Non-limiting embodiments may also tune the first flux densityinsert 322 as a vertical lamination of layers 334 and the second fluxdensity insert 324 as a horizontal lamination of layers 336, asdisplayed, with the respective layers 334 and 336 having differentsaturation flux densities. Regardless of the position, number ofconstituent layers, constituent layer orientation, and amount oftrailing box region filled, the flux density inserts 322 and 324 providemagnetic material that optimizes shielding and write pole 328 operationby being tuned to have varying saturation flux densities that are lessthan the saturation flux density of the box shield 330.

With the variety of trailing box and flux density insert configurationspossible to optimize data writing performance, the construction of adata writing magnetic element can undergo a series of general andspecific steps and decisions. FIG. 9 provides an example data writerfabrication routine 350 conducted in accordance with various embodimentsto tune the shielding of a write pole through the construction of atleast one flux density insert. The routine 350 can begin by evaluatingwhether a box shield is to be employed in the data writer in decision352. If a box shield is to be installed, step 354 deposits a leadingshield uptrack from a write pole and aligned along the medianlongitudinal axis of the write pole.

In the event a box shield is not to be utilized or at the conclusion ofstep 354, step 356 deposits a write pole with sidewalls angled atpredetermined angles. While the formation of a write pole trench shouldbe understood as included into step 356, such action is not required tobe done concurrently with the formation of the side shields. Forexample, the side shields may be formed and then subsequently patternedso that a write pole trench may be created through the removal of shieldmaterial in step 358 that forms side shields on opposite lateral sidesof the write pole. Step 358 may in some embodiments include thedeposition of non-magnetic insulating material within the write poletrench with oblique incidence angle sputtering to ensure continuouscoverage of the trench.

The side shields can be configured to continuously extend uptrack fromthe write pole with specifically angled sidewalls that form a throatregion, like region 140 of FIG. 2, if no leading shield is present. Step358 may further form one or more seams defined by the side shieldmaterial contacting the existing leading shield. Next in step 360, atleast one side shield is configured with a trailing box region bypatterning a predetermined trailing box shape and position beforeremoving portions of the side shield material. Step 360 may form thetrailing box sidewalls with angled orientations, such as the sidewall ofFIG. 8, notched regions like those shown in FIG. 5, and a lateral lengththat determines how much direct contact a trailing shield will have withthe side shields.

With one or more trailing box regions formed from step 360, at least oneflux density insert is then deposited as a vertical lamination oflayers, as shown in FIG. 3, in step 362 or deposited as a horizontallamination of layers, as shown in FIG. 4. It should be understood thatsteps 362 and 364 each can comprise several depositions of differentmaterials having different saturation flux densities. Such flux densityinsert layer deposition may further involve the shaping of sidewallangles, such as 45° and 90° with respect to the X axis, to be similar ordissimilar to the angled orientation of the write pole sidewalls.Various embodiments may incorporate non-magnetic layer deposition intothe flux density inserts in steps 362 and 364 to fill the trailing boxregion with both magnetic and non-magnetic material.

The passage from step 360 through either step 362 or 364 in FIG. 9 isnot required or limiting as one flux density insert may be formed withstep 362 and a second flux density insert can be formed of step 364 toprovide an asymmetrical shielding configuration about the write pole.Conversely, it can be appreciated that using a common deposition stepbetween steps 362 and 364 for trailing box regions on opposite sides ofa write pole can result in a symmetrical shielding configuration, suchas the configuration shown in FIGS. 3 and 4. Finally, step 366 forms atrailing shield atop the trailing box regions. Such trailing shieldformation can be positioned to contact some, or none, of the sideshields while being separated from the write pole by a non-magneticinsulating material. As shown in FIG. 8, step 366 may result in thetrailing shield contacting a previously deposited flux density insert orbe separated from the flux density insert by non-magnetic material.

Through the various steps and decision of routine 350, a data writer canbe constructed with optimized magnetic shielding and write poleperformance. The tuned saturation flux density, size, position relativethe write pole, and shape of one or more flux density inserts canprovide magnetic shielding material that reduces the risk of shuntingwhile minimizing the chance of an erasure condition. The ability to tuneboth the configuration of the flux density insert and the trailing boxregion can allow for precise control of magnetic shielding and writepole operation to conform the data writer to a wide variety of datastorage environments, such as high data bit density, rotating media datastorage devices.

In addition, while the embodiments have been directed to magneticprogramming, it will be appreciated that the claimed invention canreadily be utilized in any number of other applications, including datastorage device applications. It is to be understood that even thoughnumerous characteristics and configurations of various embodiments ofthe present disclosure have been set forth in the foregoing description,together with details of the structure and function of variousembodiments, this detailed description is illustrative only, and changesmay be made in detail, especially in matters of structure andarrangements of parts within the principles of the present disclosure tothe full extent indicated by the broad general meaning of the terms inwhich the appended claims are expressed. For example, the particularelements may vary depending on the particular application withoutdeparting from the spirit and scope of the present technology.

What is claimed is:
 1. An apparatus comprising a write pole adjacent toand separated from a side shield comprising a first magnetic materialand configured with a trailing box region defined by a reduced thicknessnotch in the side shield, a vertical lamination of first and secondlayers contained in the trailing box region, the first layer comprisinga second material and the second layer comprising a third material, thefirst, second, and third materials having different saturation fluxdensities.
 2. The apparatus of claim 1, wherein the vertical laminationfurther comprises third and fourth layers.
 3. The apparatus of claim 2,wherein the third layer comprises a fourth material and the fourth layercomprises a fifth material, the first, second, third, fourth, and fifthmaterials each having different saturation flux densities.
 4. Theapparatus of claim 3, wherein the first material has a greatersaturation flux density than the second, third, fourth, and fifthmaterials, the second material has a greater saturation flux densitythan the third, fourth, and fifth materials, the third material has agreater saturation flux density than the fourth and fifth materials, andthe fourth material has a greater saturation flux density than the fifthmaterial.
 5. The apparatus of claim 3, wherein the second material isposition proximal the write pole and the fifth material is positioneddistal to the write pole.
 6. The apparatus of claim 3, wherein the fifthmaterial is positioned proximal the write pole and the second materialis positioned distal the write pole.
 7. The apparatus of claim 1,wherein the trailing box region extends from a downtrack position to anuptrack plane parallel with a trailing edge of the write pole.
 8. Theapparatus of claim 7, wherein the uptrack plane is positioned between aleading tip of the write pole and the trailing edge of the write pole.9. The apparatus of claim 1, wherein the vertical lamination contactsthe side shield and a trailing shield.
 10. An apparatus comprising awrite pole separated from and disposed between first and second sideshields, the first and second side shields each comprising a firstmagnetic material and configured with a trailing box region defined by areduced thickness notch in the respective side shields, each trailingbox region is filled with a vertical lamination of first and secondlayers contained in the trailing box region, the first layer comprisinga second material and the second layer comprising a third material, thefirst, second, and third materials having different saturation fluxdensities.
 11. The apparatus of claim 10, wherein the verticallaminations of the first and second side shields are physicallyseparated by a non-magnetic gap material and the write pole.
 12. Theapparatus of claim 10, wherein the first and second shields aresymmetric about a longitudinal axis of the write pole.
 13. The apparatusof claim 10, wherein each vertical lamination and side shield form anasymmetric shield.
 14. The apparatus of claim 10, wherein each verticallamination has a lower saturation flux density than the first or secondside shields and a higher saturation flux density than a non-magneticgap material that surrounds the write pole.
 15. The apparatus of claim10, wherein the side shields do not physically touch and are separatedby a non-magnetic gap material.
 16. The apparatus of claim 10, whereineach side shield contacts a trailing shield adjacent to the respectivetrailing box regions.
 17. An apparatus comprising a write pole adjacentto and separated from a first side shield and a trailing shield, thefirst side shield comprising a first magnetic material and configuredwith a trailing box region defined by a reduced thickness notch in theside shield, a vertical lamination of first and second layers containedin the trailing box region, each layer extending from a non-magneticmaterial to a trailing box sidewall along a direction perpendicular to alongitudinal axis of the write pole, the first layer comprising a secondmaterial and the second layer comprising a third material, the first,second, and third materials having different saturation flux densities.18. The apparatus of claim 17, wherein the side shield sidewall isoriented at a non-zero angle with respect to the longitudinal axis ofthe write pole.
 19. The apparatus of claim 18, wherein each layer of thevertical lamination has a tapered edge oriented parallel to the sideshield sidewall.